I'm a novice and learning sayc. It seems that in recent sayc booklet and some other materials, limit raise only requires 3 cards support. Like 1♠-3♠ only promises 3 cards support. If I have game-forcing value, then start with 2/1. But some people keep telling me, limit raise should require 4 cards support. If only 3 cards with invitational value (10-11), I should use 2/1 first, like 1♠-2♣-2♦-3♠ to show 3 card support and invitational strength. This seems also very reasonable. By this I mean, if I have game-forcing value, I can bid 1♠-2♣-2♦-4♠ to make a difference from the former. May I ask which approach is standard in modern sayc?